Alkylamino mercaptoalkylamides and their use as a reducing agent in a process for the permanent deformation of hair

ABSTRACT

Alkylamino-mercaptoalkylamides have the formula ##STR1## where in A represents the divalent radical --(CH 2 ) n  --, wherein n is a whole number ranging from 2 to 5, or the divalent radical --(CH 2 ) 2  --O--(CH 2 ) 2  --, 
     m is 0, 1 or 2, 
     R 1  represents hydrogen or linear or branched lower alkyl having 1-5 carbon atoms, 
     R 2  and R 3 , each independently, represent hydrogen or a linear or branched lower alkyl having 1-4 carbon atoms with the proviso that R 2  and R 3  are not hydrogen simultaneously and the salts of the compound of formula I as well as the corresponding disulfides with the exclusion of the disulfide in which A═--(CH 2 ) 2  --, m═0, R 1  and R 2  ═H and R 3  ═--C 2  H 5 . The compound of formula I is used as a reducing agent in a cosmetic composition for the permanent deformation of hair.

The present invention relates to new alkylamino mercaptoalkylamides orone of their cosmetically acceptable salts and to their use, as reducingagents, in a process for the permanent deformation of hair.

The technique to effect the permanent deformation of hair comprises, ina first stage, effecting the opening of the disulfide bonds of keratin(cystine) using a composition containing a reducing agent (reductionstage) and then, after having preferably rinsed the hair, reconstitutingin a second stage, the said disulfide bonds by applying, on the hairunder tension, an oxidizing composition, (oxidation stage, also calledthe fixation stage), so as to impart to the hair the desired form. Thistechnique permits indifferently, to effect either the waving of the hairor uncurling or uncrisping of the hair.

Compositions to carry out the first stage of a permanent operation aregenerally provided in the form of lotions, creams, gels or powders to bediluted in a liquid support and preferably contain, as the reducingagent, a mercaptan.

Among these latter, those currently employed, are thioglycolic acid andthiolactic acid or a mixture of these acids, as well as their esters,for example, the monothioglycolate of glycerol or glycol.

These reducing agents which are particularly effective to reduce thedisulfide bonds of keratin include, principally, thioglycolic acid whichcan be considered as the product of choice in permanent wavingoperations. It provides a reduction rate of about 50 percent.

However, these reducing agents exhibit a major disadvantage in that theyemit bad odors.

With a view to remedy this disadvantage, there is generally employed aperfume so as to mask these odors.

After significant research, it has now been observed, in a quiteunexpected and surprising manner, that by using a new class ofalkylamino-mercaptoalkylamides or their cosmetically acceptable salts,it was possible to remedy the disadvantages of prior art reducingagents.

The reducing agents of the compositions in accordance with the inventionexhibit not only the advantage of being practically void of odor butthey also provide a yield, a liveliness and beauty of curling greaterthan that obtained in accordance with current techniques using, forexample, thioglycolic acid.

The present invention thus related to, as a new industrial product,alkylamino-mercaptoalkylamides having the following general formula (I)##STR2## wherein

A represents the divalent radical --(CH₂)_(n) --, wherein n represents awhole number ranging from 2 to 5, or the divalent radical --(CH₂)₂--O--(CH₂)₂ --,

m is equal to 0, 1 or 2,

R₁ represents hydrogen or linear or branched lower alkyl having 1-5carbon atoms,

R₂ and R₃, each independently, represent hydrogen or linear or branchedlower alkyl having 1-4 carbon atoms, with the proviso that R₂ and R₃ arenot hydrogen simultaneously, and the salts of said compounds of formula(I).

Among the cosmetically acceptable salts of the compounds of formula (I),those particularly preferred are the hydrochlorides, hydrobromides,citrates, oxalates and acetates.

By lower alkyl having either 1-4 or 1-5 carbon atoms is meant methyl,ethyl, propyl, isopropyl, butyl, isobutyl, 2-methylbutyl or pentyl.

Principal among the preferred compounds having the general formula (I)are the following:

2-dimethylamino N-(2-mercaptoethyl) acetamide,

2-dimethylamino N-(3-mercaptopropyl) acetamide,

2-dimethylamino N-(5-mercaptopentyl) acetamide,

2-dimethylamino N-[2'-(2-mercaptoethoxy)ethyl] acetamide,

2-diethylamino N-(2-mercaptoethyl) acetamide,

2-diethylamino N-(3-mercaptopropyl) acetamide,

2-diethylamino N-(5-mercaptopentyl) acetamide,

2-diethylamino N-[2'-(2-mercaptoethoxy)ethyl] acetamide,

2-methylamino N-(2-mercaptoethyl) acetamide,

2-methylamino N-(3-mercaptopropyl) acetamide,

2-methylamino N-(5-mercaptopentyl) acetamide,

2-methylamino N-[2'-(2-mercaptoethoxy) ethyl] acetamide,

2-ethylamino N-(2-mercaptoethyl) acetamide,

2-ethylamino N-(3-mercaptopropyl) acetamide,

2-ethylamino N-(5-mercaptopentyl) acetamide,

2-ethylamino N-[2'-(2-mercaptoethoxy) ethyl] acetamide,

2-ethylamino-2-methylamino N-(2-mercaptoethyl) acetamide,

2-propylamino N-(2-mercaptoethyl) acetamide,

2-isopropylamino N-(2-mercaptoethyl) acetamide,

2-butylamino N-(2-mercaptoethyl) acetamide,

2-ethylmethylamino N-(2-mercaptoethyl) acetamide,

3-dimethylamino N-(2-mercaptoethyl) propionamide,

3-dimethylamino N-(3-mercaptopropyl)propionamide,

3-dimethylamino N-(5-mercaptopentyl) propionamide,

3-dimethylamino N-[2'-(2-mercaptoethoxy)ethyl] propionamide,

3-methylamino N-(2-mercaptoethyl) propionamide,

3-methylamino N-(3-mercaptopropyl) propionamide,

3-methylamino N-(5-mercaptopentyl) propionamide,

3-methylamino N-[2'-(2-mercaptoethoxy) ethyl] propionamide,

2-dimethylamino N-(2-mercaptoethyl) propionamide,

2-dimethylamino N-(3-mercaptopropyl) propionamide,

2-dimethylamino N-(5-mercaptopentyl) propionamide,

2-dimethylamino N-[2'-(2-mercaptoethoxy) ethyl] propionamide,

2-methylamino N-(2-mercaptoethyl) propionamide,

2-ethylamino N-(2-mercaptoethyl) propionamide,

2-isopropylamino N-(2-mercaptoethyl) propionamide,

2-methylamino-N-(2-mercaptoethyl) butanamide,

4-dimethylamino N-(2-mercaptoethyl) butanamide,

4-dimethylamino N-(3-mercaptopropyl) butanamide,

4-dimethylamino N-(5-mercaptopentyl) butanamide,

4-dimethylamino N-[2'-(2-mercaptoethoxy) ethyl] butanamide,

4-methylamino N-(2-mercaptoethyl) butanamide,

4-ethylamino N-(2-mercaptoethyl) butanamide,

2-dimethylamino-3-methyl N-(2-mercaptoethyl) butanamide,

2-dimethylamino-4-methyl N-(2-mercaptoethyl) pentamide,

2-methylamino-4-methyl N-(2-mercaptoethyl) pentamide,

2-dimethylamino-3-methyl N-(2-mercaptoethyl) pentamide, and

2-methylamino-3-methyl N-(2-mercaptoethyl) pentanamide.

The present invention also relates to a process for preparing thealkylamino-mercapto alkylamides according to the invention. This processcomprises reacting an aminothiol (1) with an acid halide of analkylamino acid (2) so as to obtain a thioester of general formula (II)which is then rearranged into the alkylamino-mercaptoalkylamide ofgeneral formula (I) by treatment with a base, in accordance with thefollowing reaction scheme: ##STR3## wherein

A, R₁, R₂, R₃ and m have the same meanings given above for generalformula (I), and

X represents Cl or Br.

The aminothiols (1) and the acid halides of alkylaminoacids (2) areprepared following known methods, the acid halides being obtained by amethod analogous to that described, for example, in E. Fieher, Chem.Bet. 38, 2914-2934, (1905). The reaction between (1) and (2) isconducted under an inert atmosphere in an inert solvent such as, forexample, dichloromethane, 1,2-dichloroethane, 1,1,1,-trichloroethane,chloroform, acetonitrile, carbon tetrachloride, toluene, dioxane,tetrahydrofuran, 1,2-dimethoxyethane, N-methylpyrrolidone,dimethylformamide, dimethylacetamide, or a mixture of these solvents,and, depending on the boiling point of the solvent, at a temperaturebetween 40° and 110° C. The reaction time generally is less than 5hours.

The rearrangement of the thioesters of general formula (II) into thealkylamino-mercaptoalkylamides of general formula (I) is carried out inan aqueous or hydroalcoholic medium at ambient temperature and under aninert atmosphere in the presence of at least one equivalent of a basesuch as ammonia, alkaline metal hydroxides or even a tertiary amine suchas triethylamine or triethanolamine.

The present invention also relates to a reducing composition for thefirst stage of an operation for the permanent deformation of haircomprising, in a cosmetically acceptable vehicle, at least onealkylamino mercaptoalkylamide of general formula (I), as a reducingagent.

In the compositions according to the invention, the reducing agent ofgeneral formula (I) is generally present in an amount ranging from 2 to30 and preferably between 5 and 25 percent by weight based on the totalweight of the reducing composition.

The pH of the composition is preferably between 4.5 and 11 and moreparticularly between 6 and 10 and is obtained using an alkaline agentsuch as, for example, ammonia, monoethanolamine, diethanolamine,triethanolamine, an alkaline or ammonium carbonate or bicarbonate, analkaline hydroxide or using an acidifying agent such as, for example,hydrochloric acid, acetic acid, lactic acid, oxalic acid or boric acid.

The reducing composition can also contain other reducing agents such as,for example, thioglycolic acid, glycerol or glycol monothioglycolate,cysteamine and its C₁ -C₄ acyl derivatives such as, for example,N-acetylcysteamine or N-propionyl cysteamine, cysteine,N-acetylcysteine, N-mercaptoalkylamides of sugars such asN-(2-mercaptoethyl) gluconamide, β-mercaptopropionic acid and itsderivatives, thiolactic acid, thiomalic acid, pantetheine, thioglycerol,the sulfites or bisulfites of an alkali or alkaline earth metal,N-(mercaptoalkyl), ω-hydroxy-alkylamides described in EP 354 835, theN-mono- or N,N-dialkylmercapto-4-butyramides described in EP 368 763,the aminomercapto alkylamines described in EP 403 267 and thederivatives of N-(mercaptoalkyl) succinamic acids or N-(mercaptoalkyl)succinimides described in EP 465 342.

The reducing composition can also contain various ingredients such as,for example, cationic polymers such as those employed in thecompositions described in French patents No. 79.32078 and 80.26421 oreven cationic polymers of the ionene type such as those employed in thecompositions disclosed in French patent No. 82.17364, softening agentsand principally quaternary ammonium derivatives of lanolin, proteinhydrolyzates, waxes, opacifying agents, perfumes, dyes, nonionic orcationic surfactants, alcohols such as ethanol, propasol, isopropanol,1,2-propanediol, 1,2-butanediol or glycerol, treating agents or evenpenetration agents such as urea, pyrrolidone or thiomorpholinone.

The reducing composition according to the invention can also be of theexothermic type, that is to say, provoking a certain amount of heatduring application on the hair, which is agreeable to the personundergoing to the first stage of the permanent or uncurling of the hair.

The vehicle for the compositions according to the invention ispreferably water or a hydroalcoholic solution of a lower alcohol such asethanol, isopropanol or butanol.

When the compositions are intended for a hair uncurling or uncrispingoperation the reducing composition is preferably in the form of a creamso as to maintain the hair as rigid or stiff as possible. These creamsare provided in form of "heavy" emulsions, for example, those based onglyceryl stearate, glycol stearate, self-emulsifiable waxes, fattyalcohols, etc. Liquids or gels containing thickening agents, such ascarboxyvinyl polymers or copolymers which "glue" the hair can also beemployed so as to maintain the hair in a smooth position during thesetting period.

In accordance with a particular embodiment of the invention, thereducing compounds of general formula (I) can be formed in situ at thetime of use starting with their thioester precursors having thefollowing general formula ##STR4## wherein

A, R₁, R₂, R₃ and m have the same meanings as those given above forformula (I), and

X is Cl or Br.

It has been noted, in effect, that in the presence of a base such asammonia, monoethanolamine, diethanolamine, triethanolamine, soda orpotash, these thioester precursor are transformed almost instantaneouslyand quantitatively into the corresponding thiols of general formula (X).

In accordance with this embodiment, the thioester precursor in the solidstate, preferably in the form of a powder, is mixed at the time of usewith a basic aqueous solution having a pH between 8 and 10, optionallycontaining various ingredients such as those mentioned above.

The pH of the composition is then adjusted, if necessary, using analkaline agent or an acidifying agent such as those mentionedpreviously.

Thus, the present invention also relates to, as new products, thioestershaving general formula (II), above, as precursors of the alkylaminomercaptoalkylamides of general formula (I).

Principal among these thioesters are the following compounds:

the dihydrochloride of 2-aminoethyl N,N-dimethyl thioglycinate,

the dihydrochloride of 3-aminopropyl N,N-dimethyl thioglycinate,

the dihydrochloride of 5-aminopentyl N,N-dimethyl thioglycinate,

the dihydrochloride of 2'-(2-aminoethoxy) ethyl N,N-dimethylthioglycinate,

the dihydrochloride of 2-aminoethyl N,N-diethyl thioglycinate,

the dihydrochloride of 3-aminopropyl N,N-diethyl thioglycinate,

the dihydrochloride of 5-aminopentyl N,N-diethyl thioglycinate,

the dihydrochloride of 2'-(2-aminoethoxy) ethyl N,N-ethyl thioglycinate,

the dihydrochloride of 2-aminoethyl N-methyl thioglycinate,

the dihydrochloride of 3-aminopropyl N-methyl thioglycinate,

the dihydrochloride of 5-aminopentyl N-methyl thioglycinate,

the dihydrochloride of 2'-(2-aminoethoxy) ethyl N-methyl thioglycinate,

the dihydrochloride of 2-aminoethyl N-ethyl thioglycinate,

the dihydrochloride of 3-aminopropyl N-ethyl thioglycinate,

the dihydrochloride of 5-aminopentyl N-ethyl thioglycinate,

the dihydrochloride of 2'-(2-aminoethoxy) ethyl N-ethyl thioglycinate,

the dihydrochloride of 2-aminoethyl N-ethyl-N-methyl thioglycinate,

the dihydrochloride of 2-aminoethyl N-propyl thioglycinate,

the dihydrochloride of 2-aminoethyl N-isopropyl thioglycinate,

the dihydrochloride of 2-aminoethyl N-butyl thioglycinate,

the dihydrochloride of 2-aminoethyl 3-dimethyl amino thiopropionate,

the dihydrochloride of 3-aminopropyl-3-dimethylamino thiopropionate,

the dihydrochloride of 5-aminopentyl 3-dimethylamino thiopropionate,

the dihydrochloride of 2'-(2-aminoethoxy) ethyl 3-dimethylaminothiopropionate,

the dihydrochloride of 2-aminoethyl 3-methylamino thiopropionate,

the dihydrochloride of 3-aminopropyl 3-methylamino thiopropionate,

the dihydrochloride of 5-aminopentyl 3-methylamino thiopropionate,

the dihydrochloride of 2'-(2-aminoethoxy) ethyl 3-methylaminothiopropionate,

the dihydrochloride of 2-aminoethyl N,N-dimethyl thioalaninate,

the dihydrochloride of 3-aminopropyl N,N-dimethyl thioalaninate,

the dihydrochloride of 5-aminopentyl N,N-dimethyl thioalaninate,

the dihydrochloride of 2'-(2-aminoethoxy) ethyl N,N-dimethylthioalaninate,

the dihydrochloride of 2-aminoethyl N-methyl thioalaninate,

the dihydrochloride of 2-aminoethyl N-ethyl thioalaninate,

the dihydrochloride of 2-aminoethyl N-isopropyl thioalaninate,

the dihydrochloride of 2-aminoethyl 2-methylamino thiobutyrate,

the dihydrochloride of 2-aminoethyl 4-dimethyl aminothiobutyrate,

the dihydrochloride of 3-aminopropyl 4-dimethylamino thiobutyrate,

the dihydrochloride of 5-aminopentyl 4-dimethylamino thiobutyrate,

the dihydrochloride of 2'-(2-aminoethoxy) ethyl 4-dimethylaminothiobutyrate,

the dihydrochloride of 2-aminoethyl 4-methylamino thiobutyrate,

the dihydrochloride of 2-aminoethyl 4-ethylamino thiobutyrate,

the dihydrochloride of 2-aminoethyl N,N-dimethylamino thiovalinate,

the dihydrochloride of 2-aminoethyl N,N-dimethylamino thioleucinate,

the dihydrochloride of 2-aminoethyl N-methylamino thioleucinate,

the dihydrochloride of 2-aminoethyl N,N-dimethylamino thioleoleucinate,

the dihydrochloride of 2-aminoethyl N-methylamino thioleoleucinate,

the dihydrochloride of 2-aminoethyl thiopipecolinate and thedihydrochloride of 2-aminoethyl hexahydroisothionicotinate.

The compositions according to the invention can also be in a form called"self-neutralizing" or even "self-regulated" and in this case, thereducing compound of general formula (I) is combined with at least onedisulfide either known for its use in a reducing composition for aself-neutralizing permanent or derived from a compound of generalformula (I) or one of its salts and corresponds to the following generalformula (III): ##STR5## wherein

A, R₁, R₂, R₃ and m have the same meanings as those given for generalformula (I) with the exclusion of the compounds of formula (III) iswhich:

A═--(CH₂)₂ --, m=0,

R₁ and R₂ ═H and R₃ ═--C₂ H₅.

The disulfide can also be provided in the form of a cosmeticallyacceptable salt.

Among the known disulfides, there can principally be mentioneddithioglycolic acid, dithioglycerol, cystamine, N,N'-diacetyl-cystamine,cystine, pantethine, the disulfides of N-(mercaptoalkyl).sub.ω-hydroxyalkylamides described in EP 354.835 and the disulfides of N-monoor N,N-dialkylmercapto-4 butyramides described in EP 368,763, thedisulfides of aminomercaptoalkylamides described in EP 403,267, and thedisulfides of the derivatives of N-(mercaptoalkyl) succinamic acids orN-(mercaptoalkyl) succinimides described in EP 465 342.

Among the disulfides derived from a compound of general formula (I) andcorresponding to general formula (III) there can principally bementioned:

N,N'-(2,1-dithiodiethanediyl) bis [2-dimethyl amino acetamide],

N,N'-(2,1-dithiodiethanediyl) bis [2-dimethyl amino propionamide],

N,N'-(2,1-dithiodiethanediyl) bis [3-dimethyl amino propionamide],

N,N'-(2,1-dithiodiethanediyl) bis [4-dimethyl amino butyramide],

N,N'-(2,1-dithiodiethanediyl) bis [2-methyl amino acetamide],

N,N'-[dithiobis(trimethylene)] bis [2-dimethyl amino acetamide],

N,N'-[dithiobis (pentamethylene)] bis [2-dimethyl amino acetamide],

N,N'-[dithiobis (2-ethoxyethyl)] bis [2-dimethyl amino acetamide],

N,N'-(2,1-dithiodiethanediyl) bis [3-methyl amino propionamide],

N,N'-)(2,1-dithiodiethanediyl) bis [2-diethyl amino acetamide], and

N,N'-(2,1-dithiodiethanediyl) bis [2-ethyl amino acetamide].

In the self-neutralizing compositions the disulfide is generally presentin a molar ratio of 0.5 to 2.5 and preferably from 1 to 2 relative tothe compounds of general formula (I) or its salts (see U.S. Pat. No.3,768,490).

The disulfides of general formula (III) are obtained by oxidation of thecompounds of general formula (I) either in air or by using knownoxidants such as, for example, H₂ O₂ in the presence, optionally, ofmetallic salts such as, for example, ferrous salts.

The present invention also relates to a process for the permanentdeformation of hair comprising, in a first stage, reducing the disulfidebonds of keratin by applying to the hair for a period of about 5 to 60minutes, a reducing composition, such as defined above, and then in asecond stage, reforming the said bonds by applying to the hair anoxidizing composition or optionally by letting the oxygen of the air acton the hair.

The present invention also relates to a process for waving the hair inwhich a reducing composition, such as defined above, is applied tomoistened hair previously rolled up on rollers having a diameter of 4 to20 mm. The composition can optionally be applied while rolling up thehair. The reducing composition is then permitted to act on the hair fora period of time ranging from 5 to 60 minutes, preferably 5 to 30minutes. The hair is then thoroughly rinsed, after which there isapplied to the rolled up hair, an oxidizing composition so as to reformthe disulfide bonds of the keratin during a setting period of 2 to 10minutes. After having removed the rollers, the hair is thoroughlyrinsed.

The oxidizing composition, or oxidant, is of the type currently employedand contains as the oxidizing agent H₂ O₂, an alkaline bromate, apersalt, a polythionate or a mixture of an alkaline bromate and apersalt. The concentration of H₂ O₂ can vary from 1 to 20 volumes andpreferably from 1 to 10 volumes; the concentration of alkaline bromate,from 2 to 12 percent; and that of the persalt from 0.1 to 15 percent byweight relative to the total weight of the oxidizing composition. The pHof the oxidizing composition is generally between 2 and 10. Thisoxidation can be carried out immediately or be deferred.

The present invention also relates to a process for uncurling oruncrisping the hair which comprises applying to the hair a reducingcomposition, in accordance with the invention, submitting the hair to amechanical deformation so as to fix the hair in a new form, by asmoothing the hair with a large tooth comb, with the back of a comb orwith the hand. After a setting period of 5 to 60 minutes, particularly 5to 30 minutes, the hair is again smoothened and then carefully rinsed.There is then applied to the hair an oxidant or fixing agent such asdefined above which is permitted to act on the hair for about 2 to 10minutes. The hair is then thoroughly rinsed.

There are now given as an illustration and without any limitingcharacter, several examples of the preparation of the compoundsaccording to the invention, as well as reducing compositions accordingto the invention and their use in a process for the permanentdeformation of hair.

EXAMPLES OF PREPARATION Example 1 Preparation of the Dihydrochloride of2-Aminoethyl N,N-Dimethyl Thioglycinate

To a suspension of 20 g (0.126 mole) of the hydrochloride ofN,N-dimethylglycine acid chloride in 120 cm³ of anhydrous acetonitrile,there are added, under an inert atmosphere and with stirring, 14.38 mg(0.126 mole) of cysteamine hydrochloride. The mixture is then heated 3hours at 75°-80° C. After cooling to +5° C., the crude thioester (29.6g) is filtered off and purified by recrystallization in methanol. Afterdrying under a vacuum at 40°-50° C., 19.5 g of the dihydrochloride of2-aminoethyl N,N-dimethyl thioglycinate are obtained in the form of awhite solid whose melting point is 191°-193° C.

The NMR¹ H 250 MHz spectrum conforms to the expected structure as doesthe chloride dosage (Found--8.6 meq/g; Calculated 8.5 meq/g).

    ______________________________________                                        Elemental analysis: C.sub.6 H.sub.14 N.sub.2 OS.2HCl                                 C %   H %     N %     O %   S %   Cl %                                 ______________________________________                                        Calculated                                                                             30.64   6.86    11.91 6.80  13.63 30.15                              Found    30.30   6.94    10.79 6.71  13.56 30.00                              ______________________________________                                    

Example 2 Preparation of the Hydrochloride of2-Dimethylamino-N-(2-Mercaptoethyl) Acetamide

To a suspension of 11.76 g (0 05 mole) of the dihydrochloride of2-aminoethyl N,N-dimethyl thioglycinate, obtained in Example 1, in 100cm³ of isopropanol, there are slowly added, over a period of about 10minutes, at ambient temperature under an inert atmosphere and withstirring, 41 g of a 5% aqueous ammonia solution. The resulting solutionis then evaporated to dryness under reduced pressure. 50 cm³ of drychloroform are added and the ammonium chloride is filtered off on afritted glass. The filtrate is evaporated to dryness under reducedpressure. A gel is obtained which slowly crystallizes at ambienttemperature. The resulting crystals are taken up in 40 cm³ of anhydrousethyl acetate, filtered and dried under a vacuum at 50° C.

9.4 g of the hydrochloride of 2-dimethylamino N-(2-mercaptoethyl)acetamide are obtained in the form of a white solid whose melting pointis 76° C.

The NMR¹ H 250 MHz and ¹³ C spectra conform to the expected structure.

    ______________________________________                                        Elemental analysis: C.sub.6 H.sub.14 N.sub.2 OS.HCl                                  C %   H %     N %     O %   S %   Cl %                                 ______________________________________                                        Calculated                                                                             36.27   7.61    14.10 8.05  16.14 17.84                              Found    36.26   7.66    14.30 8.50  16.00 17.87                              ______________________________________                                    

Example 3 Preparation of N,N'-(2,1-Dithiodiethanediyl) Bis[2-Dimethylamino Acetamide] (a) The Hydrochloride ofN,N'-(2,1-Dithiodiethanediyl) bis [2-dimethylamino acetamide]

To a solution of 2 g (0.01 mole) of the hydrochloride of 2-dimethylamino N-(2-mercaptoethyl] acetamide, obtained in Example 2, in 15 cm³ ofabsolute alcohol, there is slowly added 0.55 cm³ (5 mmoles) of 110volume H₂ O₂ while maintaining the temperature lower than 25° C. A traceof ferrous sulfate is then added and the mixture is stirred for 6 hoursat ambient temperature. The reaction medium is concentrated underreduced pressure. 30 cm³ of toluene are added to the residue and themixture is again evaporated to dryness.

After drying under a vacuum at ambient temperature, 1.9 g of thehydrochloride of N,N'-(2,1-dithiodiethanediyl) bis [2-dimethylaminoacetamide] are obtained in the form of a pulverulent, very hygroscopicwhite solid.

(b) N,N'-(2,1-Dithiodiethanediyl) Bis [2-Dimethylamino Acetamide]

1.58 g (4 mmoles) of the compound obtained in (a) above are dissolved in20 ml of water, 0.67 g (8 mmoles) of sodium bicarbonate is added and themixture is evaporated to dryness under reduced pressure. The residue istaken up in 20 ml of ethanol and the sodium chloride is separated byfiltration. The filtrate is evaporated to dryness under reducedpressure. After recrystallization in acetone and drying under a vacuumat ambient temperature 1.13 g of N,N'-(2,1-dithiodiethanediyl) bis [2-dimethylamino acetamide] are obtained in the form of a white solidwhose melting point in 100° C.

The NMR¹ H 250 MHz spectrum conforms to the expected structure.

    ______________________________________                                                C %     H %    N %      O %  S %                                      ______________________________________                                        Calculated                                                                              44.69     8.13   17.37  9.92 19.89                                  Found     44.63     8.22   17.04  9.97 19.64                                  ______________________________________                                    

Example 4 Preparation of the Dihydrochloride of 2-Aminoethyl N,N-DiethylThioglycinate

To a suspension of 7 g (37 mmoles) of the hydrochloride ofN,N-diethylglycine acid chloride in 40 cm³ of anhydrous acetonitrile,there are added, under an inert atmosphere and with stirring, 4.27 g(37.5 mmoles) of cysteamine hydrochloride. The mixture is then heatedfor 3 hours at reflux.

After cooling the reaction medium to +5° C., the crude thioester (9 g)is filtered and then purified in 20 cm³ of boiling ethyl alcohol. Themixture is cooled to +10° C. and filtered. After drying under a vacuumat 50° C., 6.6. g of the dihydrochloride of 2-aminoethylN,N-diethylthioglycinate are obtained in the form of a white solid whosemelting point (with decomposition) is about 200° C.

The NMR¹³ C spectrum conforms to the expected structure as does thechloride dosage (Found--7.64 meq/g; Calculated--7.60 meq/g).

    ______________________________________                                        Elemental analysis: C.sub.8 H.sub.18 N.sub.2 OS.2HCl                                 C %   H %     N %     O %   S %   Cl %                                 ______________________________________                                        Calculated                                                                             36.50   7.66    10.64 6.08  12.18 26.94                              Found    36.30   7.61    10.68 6.18  12.03 27.16                              ______________________________________                                    

Example 5 Preparation of the Hydrochloride of 2-diethyl AminoN-(2-Mercaptoethyl) Acetamide

To as suspension of 3 g (11.4 mmoles) of the dihydrochloride of2-aminoethyl N,N-diethyl thioglycinate, obtained in Example 3, in 20 cm³of isopropanol, there are slowly added, over a period of about 20minutes, at ambient temperature under an argon atmosphere and withstirring, 8.8 cm³ of a 5% aqueous ammonia solution.

The resulting solution is evaporated to dryness under reduced pressure.The residue is dispersed in 40 cm³ of ethanol, cooled to 0° C. and theammonium chloride is filtered on fritted glass. The filtrate isevaporated to dryness under reduced pressure and dried under a vacuum at40° C. 2.4 g of the hydrochloride of 2-diethylamino N-(2-mercaptoethyl)acetamide are obtained in the form of a colorless oil.

The NMH¹ H 250 MHz spectrum conforms to the expected structure. Thethiol dosage by iodometry in an acid medium also conforms: Found 4.40meq/g--Calculated--4.41 meq/g.

Example 6 Preparation of the Dihydrochloride of 2-Aminoethyl N-MethylThioglycinate

A mixture of 63.4 g (0.44 mole) of the hydrochloride of sarcosine acidchloride and 50 g (0.44 mole) of cystsamine hydrochloride in 200 cm³ ofanhydrous acetonitrile is stirred for 2 hours at reflux under an argonatmosphere.

After cooling to +5° C., the crude thioester is separated by decantingthe solvent, then purified by recrystallization in an ethanol/methanolmixture. After drying under a vacuum at 40° C., 46 g of thedihydrochloride of 2-aminoethyl N-methyl thioglycinate are obtained inthe form of a white solid whose melting point (decomposition) is about220° C.

The NMR¹³ C spectrum conforms to the expected structure as does thechloride dosage (Found--9.06 meq/g; calculated--9.04 meq/g).

    ______________________________________                                        Elemental analysis: C.sub.5 H.sub.12 N.sub.2 OS.2HCl                                 C %   H %     N %     O %   S %   Cl %                                 ______________________________________                                        Calculated                                                                             27.16   6.38    12.67 7.23  14.50 32.06                              Found    27.20   6.44    12.48 7.60  14.22 31.80                              ______________________________________                                    

Example 7 Preparation of the Dihydrochloride of 2-Aminoethyl N-EthylThioglycinate

A suspension of 5 g (31.6 mmoles) of the hydrochloride of N-ethylglycineacid chloride and 3.6 g (31.7 mmoles) of cysteamine hydrochloride in 50cm³ of anhydrous acetonitrile is brought to the reflux with stirring andunder an inert atmosphere for 2 hours.

After cooling to +5° C., the solvent is removed by decanting and thecrude thioester is recrystallized in an ethanol/methanol mixture. Afterdrying under a vacuum at 40° C., 3.6 g of the dihydrochloride of2-aminoethyl N-ethyl thioglycinate are obtained in the form of a whitesolid whose melting point (decomposition) is close to 215° C.

The NMR¹³ C spectrum conforms to the expected structure as does thechloride dosage (Found--8.6 meq/g; calculated--8.5 meq/g).

    ______________________________________                                        Elemental analysis: C.sub.6 H.sub.14 N.sub.2 OS.2HCl                                 C %   H %     N %     O %   S %   Cl %                                 ______________________________________                                        Calculated                                                                             30.64   6.86    11.91 6.80  13.63 30.15                              Found    30.32   6.95    11.73 6.90  13.40 29.80                              ______________________________________                                    

Example 8 Preparation of the Dihydrochloride of 2-Aminoethyl N-EthylN-Methyl Thioglycinate

A suspension of 106 g (0.616 mole) of the hydrochloride of N-ethylN-methyl glycine acid chloride and 70 g (0.616 mole) of cysteaminehydrochloride in 400 cm³ of anhydrous acetonitrile is stirred for 5hours at reflux under an inert atmosphere.

After cooling to 20° C., the crude thioester is filtered (144.3 g), thenpurified by recrystallization in a 40/60 ethanol/methanol mixture. Afterdrying under a vacuum at 50° C., 110.5 g of the dihydrochloride of2-aminoethyl N-ethyl N-methyl thioglycinate are obtained in the form ofa white solid whose melting point (decomposition) is about 210° C.

The NMR¹³ C spectrum conforms to the expected structure as does thechloride dosage (Found--8.10 meq/g; Calculated--8.02 meq/g).

    ______________________________________                                        Elemental analysis: C.sub.7 H.sub.16 N.sub.2 OS.2HCl                                 C %   H %     N %     O %   S %   Cl %                                 ______________________________________                                        Calculated                                                                             33.74   7.28    11.24 6.42  12.87 28.45                              Found    33.74   7.38    10.78 6.72  12.36 27.90                              ______________________________________                                    

Example 9 Preparation of the Hydrochloride of 2-EthylmethylaminoN-(2-Mercaptoethyl) Acetamide

To a suspension of 30 g (0.12 mole) of the dihydrochloride of2-aminoethyl N-ethyl N-methyl thioglycinate, obtained in Example 7, in150 cm³ of isopropanol, stirred under argon at ambient temperature,there are slowly added, over a period of about 30 minutes, 126.4 g of a5% aqueous ammonia solution.

The resulting solution is evaporated to dryness under reduced pressure.100 cm³ of ethyl alcohol are added and the mixture is again evaporatedto dryness under reduced pressure.

The residue is taken up in 150 cm³ of ethanol with stirring, cooled to0° C. and the ammonium chloride is filtered off on fritted glass. Thefiltrate is evaporated to dryness and the residue is taken up in 200 cm³of dry chloroform. This mixture is then filtered on fritted glass so asto separate the residual ammonium chloride. The filtrate is thenevaporated to dryness and dried under a vacuum at 50° C. in a prolongedmanner. 24.5 g of the hydrochloride of 2-ethylmethylaminoN-(2-mercaptoethyl) acetamide are obtained in the form of a colorless tovery pale yellow gel.

The NMR¹ H 400 MHz and ¹³ C spectra conform to the expected structure.

The thiol dosage by iodometry in an acid medium: Found--4.65 meq/g;Calculated--4.70 meq/g.

Example 10 Preparation of the Dihydrochloride of 3-AminopropylN,N-Dimethyl Thioglycinate

A suspension of 6.5 g (41 mmoles) of the hydrochloride of N,N-dimethylglycine acid chloride and 5.25 g (41 mmoles) of the hydrochloride of3-mercaptopropylamine in 40 cm³ of anhydrous acetonitrile is stirred for4 hours at reflux under an argon atmosphere.

After cooling to +5° C., the crude thioester is filtered thenrecrystallized in an ethanol/methanol mixture. After drying at 40° C.,5.3 g of the dihydrochloride of 3-aminopropyl N,N-dimethyl thioglycinateare obtained in the form of a white solid whose melting point(decomposition) is about 215° C.

The NMR¹³ C spectrum conforms to the expected structure as does thechloride dosage (Found--8.10 meq/g; Calculated--8.02 meq/g).

    ______________________________________                                        Elemental analysis: C.sub.7 H.sub.16 N.sub.2 OS.2HCl                                 C %   H %     N %     O %   S %   Cl %                                 ______________________________________                                        Calculated                                                                             33.74   7.28    11.24 6.42  12.87 28.45                              Found    33.68   7.18    11.17 6.19  12.92 28.25                              ______________________________________                                    

Example 11 Preparation of the Dihydrochloride of 2'-(2-Aminoethoxy)ethylN-Ethyl Thioglycinate

A suspension of 5 g (31.8 mmoles) of the hydrochloride of(2-mercaptoethoxy) ethylamine and 5 g (31.6 mmoles) of the hydrochlorideof N-ethyl glycine acid chloride in 60 cm³ of anhydrous acetonitrile isheater for 3 hours at reflux with stirring and under an inertatmosphere.

After cooling to +10° C. and filtering, the crude thioester isrecrystallized in absolute ethanol. After drying under a vacuum at 50°C., 3.2 g of the dihydrochloride of 2'-(2-aminoethoxy) ethyl N-ethylthioglycinate are obtained in the form of a white solid whose meltingpoint (decomposition) is about 140° C.

The NMR¹³ C spectrum conforms to the expected structure as does thechloride dosage (Found--7.06 meq/g; Calculated--7.03 meq/g).

    ______________________________________                                        Elemental analysis: C.sub.8 H.sub.17 N.sub.2 O.sub.2 S.2HCl                          C %   H %     N %     O %   S %   Cl %                                 ______________________________________                                        Calculated                                                                             34.41   7.22    10.03 11.46 11.48 25.39                              Found    34.30   7.30    10.03 11.62 11.22 25.36                              ______________________________________                                    

Example 12 Preparation of the Dihydrochloride of 2-Aminoethyl4-Dimethylamino Thiobutyrate

A suspension of 3 g (27 mmoles) of cystsamine hydrochloride and 5 g (27mmoles) of the hydrochloride of the acid chloride of 4-dimethylaminobutyric acid in 75 ml of anhydrous acetonitrile is heated at reflux for5 hours with stirring and under an inert atmosphere.

After cooling to ambient temperature and filtering, the crude thioesteris recrystallized in an 8:2 ethanol/isoproylether mixture. After dryingunder a vacuum, 5.87 g of the dihydrochloride of 2-aminoethyl4-dimethylamino thiobutyrate are obtained in the form of a white solidwhose melting point is 112° C.

The NMH¹ H and ¹³ C spectra conform to the expected structure as doesthe chloride dosage (Found--7.72 meq/g; Calculated--7.75 meq/g).

Example 13 Preparation of the Dihydrochloride of 2-Aminoethyl2-Ethylamino Thiobutyrate

A suspension of 3.7 g (33 mmoles) of cysteamine hydrochloride and 5 g(33 mmoles) of the hydrochloride of the acid chloride of2-ethylaminobutyric acid in 100 ml of anhydrous acetonitrile is heatedat reflux for 5 hours with stirring and under an inert atmosphere.

After cooling to ambient temperature, and filtering, the crude thioesteris recrystallized in a 7:3 isopropyl alcohol/diisopropyl ether mixture.After drying under a vacuum 5.5 g of the dihydrochloride of 2-aminoethyl2-ethylamino thiobutyrate are obtained in the form of a white solidwhose melting point is 121° C.

The NMR¹ H and ¹³ C spectra conform to the expected structure as doesthe chloride dosage (Found--7.55 meq/g; calculated--7.60 meg/g).

The thioesters described in Examples 1, 4, 6, 7, 8, 10, 11 and 12exhibit good preservation capacity. It is then much more convenient totransform them into thiols in an extemporaneous manner. Thus, by theaddition of at least one equivalent of a basic agent such as ammonia,the compounds of these examples lead to the corresponding thiols in anaqueous solution with a titer greater than or equal to 99.8% (iodometryin acid medium).

EXAMPLES OF COMPOSITIONS Example A

In accordance with the invention a reducing composition for thepermanent deformation of hair is prepared by mixing the followingingredients:

    ______________________________________                                        A.    Reducing Composition                                                          Hydrochloride of 2-dimethylamino                                                                      19     g                                              N-(2-mercaptoethyl) acetamido                                                 Monoethanolamine, sufficient amount                                           for pH = 8.5                                                                  Oleocetyl dimethyl hydroxyethyl                                                                       0.3    g                                              ammonium chloride                                                             Preservative            0.2    g                                              Perfume                 0.8    g                                              Demineralized water, sufficient                                                                       100    g                                              amount for                                                              ______________________________________                                    

This composition is applied to moistened hair, previously rolled up onrollers. After letting the composition act on the hair for 15 minutes,the hair is thoroughly rinsed with water.

    ______________________________________                                        B.  Oxidizing composition                                                         H.sub.2 O.sub.2           1.5     g                                           Sodium laurylether sulfate, oxyethylenated                                                              3.75    g                                           with 2 moles of ethylene oxide                                                Citric acid               0.5     g                                           Sodium hydrogen phosphate 0.5     g                                           Perfume                   0.3     g                                           Demineralized water, sufficient amount for                                                              100     g                                       ______________________________________                                    

This oxidizing composition is left to react on the hair for about 5minutes. The rollers are then removed and the hair is thoroughly rinsedwith water. After drying under a hood, the hair exhibits beautifulcurls.

In accordance with the embodiment described is Example A, a permanentdeformation of the hair is carried out using the reducing and oxidizingcompositions of the following examples B to M:

Example B

    ______________________________________                                        A.  Reducing composition                                                          Hydrochloride of 2-dimethylamino                                                                        21      g                                           N-(2-mercaptoethyl) acetamide                                                 Ethylene diamine tetraacetic acid                                                                       0.2     g                                           Triethanolamine, sufficient amount                                            for pH = 6.8                                                                  Lauramine oxide, sold under the trade                                                                   2.15    g                                           name "AROMOX DMMCD/W" by Azko                                                 Perfume                   0.6     g                                           Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing composition                                                         H.sub.2 O.sub.2           2.0     g                                           Oleocetyl dimethyl hydroxyethyl                                                                         0.3     g                                           ammonium chloride                                                             Phosphoric acid           0.5     g                                           p-ethoxyacetanilide (phenacetin)                                                                        0.1     g                                           Protein hydrolyzate       0.5     g                                           Perfume                   0.5     g                                           Demineralized water, sufficient amount for                                                              100     g                                       ______________________________________                                    

Example C

    ______________________________________                                        A.  Reducing Composition                                                          Dihydrochloride of 2-aminoethyl                                                                         11      g                                           N,N-dimethyl thioglycinate                                                    Ammoniacal solution (20% NH.sub.3)                                                                      4.1     g                                           Monoethanolamine, sufficient amount for                                       pH = 8.0                                                                      Ammonium bicarbonate      2.0     g                                           Cocoamidopropylbetaine, sold under the                                                                  0.9     g                                           trade name "TEGOBETAINE HS" by                                                Goldschmidt                                                                   Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing Composition                                                         H.sub.2 O.sub.2           2.5     g                                           Sodium stannate           0.03    g                                           Homopolymer of N,N-dimethyl N-2                                                                         1.25    g                                           propenyl-2-propene-1-ammonium                                                 chloride (polyquaternium-6),                                                  sold under the trade name                                                     "MERQUAT 100" by Merck                                                        Citric acid               0.6     g                                           Perfume                   0.5     g                                           Demineralized water, sufficient, amount for                                                             100     g                                       ______________________________________                                    

Example D

    ______________________________________                                        A.  Reducing Composition                                                          Dihydrochloride of 2-aminoethyl                                                                         17      g                                           N,N-dimethyl thioglycinate                                                    N,N'-(2,1-dithiodiethanediyl) bis                                                                       5.1     g                                           [2-dimethylamino acetamide]                                                   Pentasodium salt of diethylene triamine                                                                 0.2     g                                           pentacetic acid                                                               Monoethyanolamine, sufficient amount                                          for pH = 8.9                                                                  Hydrogenated castor oil oxyethylenated                                                                  4       g                                           with 60 moles of ethylene oxide,                                              sold under the trade name "NKKOL                                              HCO 60" by Nikko Chemical                                                     Homopolymer of N,N-dimethyl N-2-propenyl-                                                               3.8     g                                           2-propene-1 ammonium chloride                                                 (polyquaternium 7) sold under the trade                                       name "MERQUAT 550" by Merck                                                   Perfume                   0.3     g                                           Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing Composition                                                         H.sub.2 O.sub.2 (200 volumes)                                                                           4.8     g                                           Stabilizer                0.1     g                                           D. Panthenol              1.0     g                                           4'-α-dimethyl-α-(4-methyl-3-pentenyl)-                                                      0.3     g                                           3-cyclohexane methanol (Bisabolol),                                           sold under the trade name "DRAGOSANTOL                                        2/012681" by Dragoco                                                          Lauryl dimethyl amine oxide                                                                             0.7     g                                           Perfume                   0.4     g                                           Lactic acid, sufficient amount for pH = 3.0                                   Demineralized water, sufficient amount for                                                              100     g                                       ______________________________________                                    

Example E

    ______________________________________                                        A.  Reducing Composition                                                          Dihydrochloride of 2-aminoethyl                                                                         3.5     g                                           N,N-dimethyl thioglycinate                                                    L-cysteine                5.0     g                                           Monoethanolamine, sufficient amount                                           for pH = 9.3                                                                  Stearic ester polyethylened with 8 moles                                                                1       g                                           of ethylene oxide sold under the                                              trade name "MYRJ 45" by ICI                                                   Preservative              0.4     g                                           Perfume                   0.3     g                                           Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing composition                                                         H.sub.2 O.sub.2           2.5     g                                           Sodium stannate           0.02    g                                           Ammonium lauryl sulfate   1.5     g                                           Protein hydrolyzate       0.6     g                                           Citric acid               0.5     g                                           Perfume                   0.4     g                                           Demineralized water, sufficient amount                                                                  100     g                                       ______________________________________                                    

Example F

    ______________________________________                                        A.  Reducing Composition                                                          Dihydrochloride of 2-aminoethyl                                                                           2.5    g                                          N,N-dimethyl thioglycinate                                                    N-acetylcysteamine          6.0    g                                          Ammoniacal solution, sufficient                                               amount for pH = 8.0                                                           Ammonium bicarbonate        2.0    g                                          Homopolymer of N,N-dimethyl N-2-propenyl-2                                                                2.5    g                                          propene-1 ammonium chloride                                                   (polyquaternium-6) sold under the                                             trade name "MERQUAT 100" by Merck                                             Collagen hydrolyzate        0.5    g                                          Oleocetyldimethyl hydroxyethyl                                                                            1.0    g                                          ammonium chloride                                                             Perfume                     0.8    g                                          Demineralized water, sufficient                                                                           100    g                                          amount for                                                                B.  Oxidizing Composition                                                         H.sub.2 O.sub.2 (200 volumes)                                                                             4.8    g                                          Stabilizer                  0.1    g                                          D. Panthenol                1.0    g                                          4'-α-dimethyl-α-(4-methyl-3-pentenyl)-                                                        0.3    g                                          3-cyclohexene methanol (Bisabolol)                                            sold under the trade name "DRAGOSANTOL                                        2/012681" by Dragoco                                                          Lauryl dimethyl amine oxide 0.7    g                                          Perfume                     0.4    g                                          Lactic acid, sufficient amount for pH = 3.0                                   Demineralized water, sufficient amount for                                                                100    g                                      ______________________________________                                    

Example G

    ______________________________________                                        A.  Reducing Composition                                                          Dihydrochloride of 2-aminoethyl                                                                         2.0     g                                           N,N-dimethyl thioglycinate                                                    N-propionyl cysteamine    6.5     g                                           Monoethanolamine, sufficient amount                                           for pH = 8.5                                                                  Cetyl trimethyl ammonium chloride                                                                       1.0     g                                           Perfume                   0.6     g                                           Preservative              0.15    g                                           Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing Composition                                                         Sodium bromate            8       g                                           Triethanolamine, sufficient amount for pH = 8.0                               Hydrated monosodium phosphate (12H.sub.2 O)                                                             0.3     g                                           Hydrated trisodium phosphate (2H.sub.2 O)                                                               0.5     g                                           Cocoamidopropylbetaine, sold under the                                                                  1.0     g                                           trade name "TEGOBETAINE HS" by                                                Goldschmidt                                                                   Perfume                   0.4     g                                           Demineralized water, sufficient amount for                                                              100     g                                       ______________________________________                                    

Example H

    ______________________________________                                        A.  Reducing Composition                                                          Dihydrochloride of 2-aminoethyl                                                                         2.0     g                                           N,N-dimethyl thioglycinate                                                    Cysteamine hydrochloride  5.2     g                                           Monoethanolamine, sufficient amount                                           for pH = 9.5                                                                  Cetyl trimethyl ammonium chloride                                                                       1.0     g                                           Perfume                   0.6     g                                           Preservative              0.15    g                                           Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing composition                                                         Sodium bromate            8       g                                           Triethanolamine, sufficient amount for pH = 8.0                               Hydrated monosodium phosphate (12H.sub.2 O)                                                             0.3     g                                           Hydrated trisodium phosphate (2H.sub.2 O)                                                               0.5     g                                           Cocoamidopropylbetaine, sold under the                                                                  1.0     g                                           trade name "TEGOBETAINE HS" by                                                Goldschmidt                                                                   Perfume                   0.4     g                                           Demineralized water, sufficient amount for                                                              100     g                                       ______________________________________                                    

Example I

    ______________________________________                                        A.  Reducing Composition                                                          Dihydrochloride of 2-aminoethyl                                                                         8       g                                           N-ethyl N-methyl thioglycinate                                                Laurylamino oxide, sold under the                                                                       2       g                                           trade name "AROMOX DMMCD/W",                                                  by Akzo                                                                       Ethylene diamine tetraacetic acid                                                                       0.15    g                                           Perfume, sufficient amount                                                    Monoethanolamine, sufficient amount                                           for pH = 8.1                                                                  Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing composition                                                         H.sub.2 O.sub.2           2       g                                           Sodium stannate           0.015   g                                           Ammonium lauryl sulfate   1.4     g                                           Protein hydrolyzate       0.6     g                                           Citric acid               0.5     g                                           Perfume, sufficient amount                                                    Demineralized water, sufficient amount for                                                              100     g                                       ______________________________________                                    

Example J

    ______________________________________                                        A.  Reducing Composition                                                          Dihydroxychloride of 2-aminoethyl                                                                       19      g                                           N-ethylthioglycinate                                                          Laurylamine oxide, sold under the                                                                       2       g                                           trade name "AROMOX DMMCD/W"                                                   by Akzo                                                                       Homopolymer of N,N-dimethyl N-2 propenyl-2                                                              1.10    g                                           propene-1 chloride (polyquaternium-6),                                        sold under the trade name "MERQUATE 100"                                      by Merck                                                                      Perfume, sufficient amount                                                    Ammonia (20%), sufficient amount for                                          pH = 8.6                                                                      Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing Composition                                                         This composition is identical to that of Example I.                       ______________________________________                                    

Example K

    ______________________________________                                        A.  Reducing Composition                                                          Dihydrochloride of 2-aminoethyl                                                                         12      g                                           N,N-dimethyl thioglyciante                                                    Stearic ester polyethylened with 8 moles                                                                0.85    g                                           of ethylene oxide, sold under the                                             trade name "MYRJ 45" by ICI                                                   Preservative              0.35    g                                           Perfume, sufficient amount                                                    Monoethanolamine, sufficient amount for pH = 8.8                              Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing Composition                                                         This composition is identical to that in Example I.                       ______________________________________                                    

Example L

    ______________________________________                                        A.  Reducing composition                                                          Dihydrochloride of 2-aminoethyl                                                                         20      g                                           N-methyl thioglycinate                                                        Laurylamine oxide, sold under the                                                                       2       g                                           trade name "AROMOX DMMCD/W"                                                   by Akzo                                                                       Preservative              0.15    g                                           Perfume, sufficient amount                                                    Monoethanolamine, sufficient amount                                           for pH = 7.8                                                                  Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing Composition                                                         This composition is identical to that in Example I.                       ______________________________________                                    

Example M

    ______________________________________                                        A.  Reducing Composition                                                          Dihydrochloride of 2-aminoethyl                                                                         7.2     g                                           N,N-diethyl thioglycinate                                                     Oleocetyl dimethyl hydroxyethyl                                                                         0.3     g                                           ammonium chloride                                                             Preservative              0.15    g                                           Perfume, sufficient amount                                                    Ammonia, sufficient amount for pH = 8.0                                       Demineralized water, sufficient amount for                                                              100     g                                       B.  Oxidizing Composition                                                         This composition is identical to that of Example I.                       ______________________________________                                    

We claim:
 1. A compound having the formula ##STR6## wherein A representsthe divalent radical --(CH₂)_(n) -- wherein n is a whole number rangingfrom 2 to 5 or the divalent radical --(CH₂)₂ --O--(CH₂)₂ --,m is equalto 0, 1 or 2, R₁ represents hydrogen or a linear or branched lower alkylhaving 1-5 carbon atoms, R₂ and R₃, each independently, representhydrogen or linear or branched lower alkyl having 1-4 carbon atoms, withthe proviso that R₂ and R₃ do not simultaneously represent hydrogen andthe salts of said compound of formula I.
 2. The compound of claim 1selected form the group consisting of:2-dimethylaminoN-(2-mercaptoethyl) acetamide, 2-dimethylamino N-(3-mercaptopropyl)acetamide, 2-dimethylamino N-(5-mercaptopentyl) acetamide,2-dimethylamino N-[2'-(2-mercaptoethoxy)ethyl] acetamide, 2-diethylaminoN-(2-mercaptoethyl) acetamide, 2-diethylamino N-(3-mercaptopropyl)acetamide, 2-diethylamino N-(5-mercaptopentyl) acetamide, 2-diethylaminoN-[2'-(2-mercaptoethoxy)ethyl] acetamide, 2-methylaminoN-(2-mercaptoethyl) acetamide, 2-methylamino N-(3-mercaptopropyl)acetamide, 2-methylamino N-(5-mercapto pentyl) acetamide, 2-methylaminoN-[2'-(a-mercaptoethoxy) ethyl] acetamide, 2-ethylaminoN-(2-mercaptoethyl) acetamide, 2-ethylamino N-(3-mercaptopropyl)acetamide, 2-ethylamino N-(5-mercaptopentyl) acetamide, 2-ethylaminoN-[2'-(2-mercaptoethoxy) ethyl] acetamide, 2-ethylamino-2-methylaminoN-(2-mercaptoethyl) acetamide, 2-propylamino N-(2-mercaptoethyl)acetamide, 2-isopropylamino N-(2-mercaptoethyl) acetamide, 2-butylaminoN-(2-mercaptoethyl) acetamide, 2-ethylmethylamino N-(2-mercaptoethyl)acetamide, 3-dimethylamino N-(2-mercaptoethyl) propionamide,3-dimethylamino N-(3-mercaptopropyl)propionamide, 3-dimethylaminoN-(5-mercaptopentyl) propionamide, 3-dimethylaminoN-[2'-(2-mercaptoethoxy)ethyl] propionamide, 3-methylaminoN-(2-mercaptoethyl) propionamide, 3-methylamino N-(3-mercaptopropyl)propionamide, 3-methylamino N-(5-mercaptopentyl) propionamide,3-methylamino N-[2'-(2-mercaptoethoxy) ethyl] propionamide,2-dimethylamino N-(2-mercaptoethyl) propionamide, 2-dimethylaminoN-(3-mercaptopropyl) propionamide, 2-dimethylamino N-(5-mercaptopentyl)propionamide, 2-dimethylamino N-[2'-(2-mercaptoethoxy) ethyl]propionamide, 2-methylamino N-(2-mercaptoethyl) propionamide,2-ethylamino N-(2-mercaptoethyl) propionamide, 2-isopropylaminoN-(2-mercaptoethyl) propionamide, 2-methylamino-N-(2-mercaptoethyl)butanamide, 4-dimethylamino N-(2-mercaptoethyl) butanamide,4-dimethylamino N-(3-mercaptopropyl) butanamide, 4-dimethylaminoN-(5-mercaptopentyl) butanamide, 4-dimethylaminoN-[2'-(2-mercaptoethoxy) ethyl] butanamide, 4-methylaminoN-(2-mercaptoethyl) butanamide, 4-ethylamino N-(2-mercaptoethyl)butanamide, 2-dimethylamino-3-methyl N-(2-mercaptoethyl) butanamide,2-dimethylamino-4-methyl N-(2-mercaptoethyl) pentamide,2-methylamino-4-methyl N-(2-mercaptoethyl) pentamide,2-dimethylamino-3-methyl N-(2-mercaptoethyl) pentamide, and2-methylamino-3-methyl N-(2-mercaptoethyl) pentanamide.
 3. A compositionfor the first stage of an operation for the permanent deformation ofhair comprising, in a cosmetically acceptable vehicle for the hair, as areducing agent at least one alkylamino-mercaptoalkylamide having thefollowing general formula ##STR7## wherein A represents the divalentradical --(CH₂)_(n) -- wherein n is a whole number ranging from 2 to 5or the divalent radical --(CH₂)₂ --O--(CH₂)₂ --,m is 0, 1 or 2, R₁represents hydrogen or a linear or branched lower alkyl having 1-5carbon atoms, R₂ and R₃, each independently, represent hydrogen orlinear or branched lower alkyl having 1-4 carbon atoms, with the provisothat R₂ and R₃ do not simultaneously represent hydrogen, and a salt ofsaid compound of formula (I).
 4. The composition of claim 3 wherein saidsalt of the compound of formula (I) is selected from the groupconsisting of hydrochloride, hydrobromide, citrate, oxalate and acetate.5. The composition of claim 3 wherein said compound is selected from thegroup consisting of2-dimethylamino N-(2-mercaptoethyl) acetamide,2-dimethylamino N-(3-mercaptopropyl) acetamide, 2-dimethylaminoN-(5-mercaptopentyl) acetamide, 2-dimethylaminoN-[2'-(2-mercaptoethoxy)ethyl] acetamide, 2-diethylaminoN-(2-mercaptoethyl) acetamide, 2-diethylamino N-(3-mercaptopropyl)acetamide, 2-diethylamino N-(5-mercaptopentyl) acetamide, 2-diethylaminoN-[2'-(2-mercaptoethoxy)ethyl] acetamide, 2-methylaminoN-(2-mercaptoethyl) acetamide, 2-methylamino N-(3-mercaptopropyl)acetamide, 2-methylamino N-(5-mercaptopentyl) acetamide, 2-methylaminoN-[2'-(2-mercaptoethoxy) ethyl] acetamide, 2-ethylaminoN-(2-mercaptoethyl) acetamide, 2-ethylamino N-(3-mercaptopropyl)acetamide, 2-ethylamino N-(5-mercaptopentyl) acetamide, 2-ethylaminoN-(2'(2-mercaptoethoxy) ethyl] acetamide, 2-ethylamino-2-methylaminoN-(2-mercaptoethyl) acetamide, 22-propylamino N-(2-mercaptoethyl)acetamide, 2-isopropylamino N-(2-mercaptoethyl) acetamide, 2-butylaminoN-(2-mercaptoethyl) acetamide, 2-ethylmethylamino N-(2-mercaptoethyl)acetamide, 3-dimethylamino N-(2-mercaptoethyl) propionamide,3-dimethylamino N-(3-mercaptopropyl)propionamide, 3-dimethylaminoN-(5-mercaptopentyl) propionamide, 3-dimethylaminoN-[2'-(2-mercaptoethoxy)ethyl] propionamide, 3-methylaminoN-(2-mercaptoethyl) propionamide, 3-methylamino N-(3-mercaptopropyl)propionamide, 3-methylamino N-(5-mercaptopentyl) propionamide,3-methylamino N-[2'-(2-mercaptoethoxy) ethyl] propionamide,2-dimethylamino N-(2-mercaptoethyl) propionamide, 2-dimethylaminoN-(3-mercaptopropyl) propionamide, 2-dimethylamino N-(5-mercaptopentyl)propionamide, 2-dimethylamino N-[2'-(2-mercaptoethoxy) ethyl]propionamide, 2-methylamino N-(2-mercaptoethyl) propionamide,2-ethylamino N-(2-mercaptoethyl) propionamide, 2-isopropylaminoN-(2-mercaptoethyl) propionamide, 2-methylamino-N-(2-mercaptoethyl)butanamide, 4-dimethylamino N-(2-mercaptoethyl) butanamide,4-dimethylamino N-(3-mercaptopropyl) butanamide, 4-dimethylaminoN-(5-mercaptopentyl) butanamide, 4-dimethylaminoN-[2'-(2-mercaptoethoxy) ethyl] butanamide, 4-methylaminoN-(2-mercaptoethyl) butanamide, 4-ethylamino N-(2-mercaptoethyl)butanamide, 2-dimethylamino-3-methyl N-(2-mercaptoethyl) butanamide,2-dimethylamino-4-methyl N-(2-mercaptoethyl) pentamide,2-methylamino-4-methyl N-(2-mercaptoethyl) pentamide,2-dimethylamino-3-methyl N-(2-mercaptoethyl) pentamide, and2-methylamino-3-methyl N-(2-mercaptoethyl) pentanamide.
 6. Thecomposition of claim 3 wherein said compound of formula (I) is formed insitu from its thioester precursor having the following formula (II):##STR8## wherein A, R₁, R₂, R₃ and m have the same meanings given inclaim 3 for formula (I) and X is Cl or Br.
 7. The composition of claim 3wherein said compound of formula (I) is present in an amount rangingfrom 2 to 30 percent by weight based on the total weight of saidcomposition.
 8. The composition of claim 3 wherein said compound offormula (I) is present in an amount ranging form 5 to 25 percent byweight based on the total weight of said composition.
 9. The compositionof claim 6 wherein said compound of formula (II) is present in an amountranging from 2 to 30 percent by weight base don the total weight of saidcomposition,
 10. The composition of claim 6 wherein said compound offormula (II) is present in an amount ranging from 5 to 25 percent byweight based on the total weight of said composition.
 11. Thecomposition of claim 3 having a pH ranging from 4.5 to 11 obtained bythe presence of an alkaline agent selected from the group consisting ofammonia, monoethanolamine, diethanolamine, triethanolamine, an alkalineor ammonium carbonate or bicarbonate, and alkaline hydroxide, or thepresence of an acidifying agent selected from the group consisting ofhydrochloric acid, acetic acid, lactic acid, oxalic acid and boric acid.12. The composition of claim 11 having a pH ranging from 6 to
 10. 13.The composition of claim 3 which also contains at least one otherreducing agent selected from the group consisting of thioglycolic acid,glycerol or glycol monothioglycolate, cysteamine or its C₁ -C₄ acylderivatives, cysteine, N-acetylcysteine, N-mercaptoalkylamide of asugar, β-mercaptopropionic acid or a derivative thereof, thiolacticacid, thiomalic acid, pantetheine, thioglycerol, a sulfite or bisulfiteof an alkali or alkaline earth metal, an N-(mercaptoalkyl)ω-hydroxyalkylamide, an N-mono- N,N-dialkyl mercapto 4-butyramide, anaminomercaptoalkylamide and a derivative of an N-(mercaptoalkyl)succinamic acid or N-(mercaptoalkyl) succinimide.
 14. The composition ofclaim 3 which also contains at least one of a cationic polymer, asoftening agent, a protein hydrolyzate, a wax, an opacifying agent, aperfume, a dye, a nonionic surfactant, an alcohol, a treating agent or apenetration agent.
 15. The composition of claim 3, which also containsat least one disulfide, said composition being a self-neutralizingcomposition.
 16. The composition of claim 15 wherein said disulfide isselected form the group consisting of dithioglycolic acid,dithioglycerol, cystamine, N,N'-diacetylcystamine, cystine, panthetine,a disulfide of N-(mercaptoalkyl)ω-hydroxyalkylamide or of N-mono orN,N-dialkyl mercapto 4-butyramide, a disulfide ofaminomercaptoalkylamide, a disulfide of a derivative of anN-(mercaptoalkyl) succinamic acid or of an N-(mercaptoalkyl) succinimide17. The composition of claim 15 wherein said disulfide has the formula(III) ##STR9## A represents the divalent radical --(CH₂)_(n) -- whereinn is a whole number ranging from 2 to 5 or the divalent radical --(CH₂)₂--O--(CH₂)₂ --,m is 0, 1 or 2, R₁ represents hydrogen or a linear orbranched lower alkyl having 1-5 carbon atoms, R₂ and R₃, eachindependently, represent hydrogen or linear or branched lower alkylhaving 1-4 carbon atoms, with the proviso that R₂ and R₃ are nothydrogen simultaneously and with the exclusion of the compound offormula (III) wherein A═--(CH₂)₂ --, m═0, R₁ and R₂ ═H and R₃ ═--C₂ H₅.18. The composition of claim 17 wherein said disulfide of formula (III)is selected from the group consisting ofN,N'-(2,1-dithiodiethanediyl)bis [2-dimethyl amino acetamide], N,N'-(2,1-dithiodiethanediyl) bis[2-dimethyl amino propionamide], N,N'-(2,1-dithiodiethanediyl) bis[3-dimethyl amino propionamide], N,N'-(2,1-dithiodiethanediyl) bis[4-dimethyl amino butyramide], N,N'-(2,1-dithiodiethanediyl) bis [2-methyl amino acetamide], N,N'-[dithiobis(trimethylene)] bis [2-dimethylamino acetamide], N,N'-[dithiobis (pentamethylene)] bis [2-dimethylamino acetamide], N,N'-[dithiobis (2-ethoxyethyl)] bis [2-dimethyl aminoacetamide], N,N'-(2,1-dithiodiethanediyl) bis [3-methyl aminopropionamide], N,N'-) (2,1-dithiodiethanediyl) bis [2-diethyl aminoacetamide], and N,N'-(2,1-dithiodiethanediyl) bis [2 -ethyl aminoacetamide].
 19. The composition of claim 15 wherein said disulfide ispresent in a molar proportion, relative to the compound of formula (I)ranging from 0.5 to 2.5.
 20. The composition of claim 15 wherein saiddisulfide is present in a molar proportion, relative to the compound offormula (I) ranging from 1 to
 2. 21. A process for the permanentdeformation of hair comprising, in a first stage, applying to the hairthe reducing composition of claim 3 so as to reduce the disulfide bondsof keratin and in a second stage applying to the hair an oxidizingcomposition so as to reform said disulfide bond.
 22. The process ofclaim 21 wherein said reducing composition, applied to said hair, ispermitted to act on said hair for a period of time ranging from 5 to 60minutes.